Update internal links inside of this repo to point to jellyfin-roku-legacy, not jellyfin-roku

[brianpardy]

While describing to someone how to sideload an older version of the Roku app, I noticed that the "latest build" link in the Beta Test section points to the jellyfin/jellyfin-roku repo, and should probably be updated to the jellyfin/jelly-roku-legacy repo. Otherwise people looking for old builds will be directed to post-3.0.0 releases.

[cewert]

All the links in the release notes are also broken which is a bummer

[jimdogx]

The legacy app was going to be archived. However it turns out there are a handful of people that are "stuck" on Jellyfin Server 10.8 (which is a bummer because it has security issues etc). So we're keeping 2.3.1 around until folks can figure out how to upgrade.

Therefore the readme needs more than just the links updated:

Logo is no longer accurate (but since it's Legacy that's probably fine).
We can remove Build status
We can remove Translation status
We can remove the "open an issue" part.
I'm on the fence about the "latest build"... we want people to install the new one and not this one. So this section probably needs to be re-worked to explain all of that.
We can remove the "feature request" section.

[jimdogx]

Also as a reminder, a Legacy version of the app comes out in the Roku stores today (at 10 am Pacific time). Therefore, people shouldn't really need to side-load v2.3.1 anymore.